Brake



arch 23, 1937. v J. w. TATTER 2,074,710

BRAKE Original Filed May 14, 1930 I A 1N VEN TOR. f/w W 72x21 TTORNEY.

Patented Mar'. 23, 1937 PATENT GFFICE amarlo nam John W. Tatter, Akron,Ohio, assigner to Bendix Products Corporation, South Bend, 1nd., acorporation of Indiana Reille of abandoned 452,388, May 14, 1930.

application Serial No.

'llhis application Jun 19, 1936, Serial No. 86,067

14 Claims.

This is a reille of my abandoned application Serial No. 452,388, ledMayl 14, 1930.

lilly invention relates .to brakes and more particularly to. thattype'of brakes adapted for use p with automobile vehicles and the like,though it will be understood that the principles of my invention may beincorporated in braking mechanisms for aircraft or other types ofmachinery.

ln the duid type of brake as well'as with a i@ mechanically operatedbrake, good braking emciency at all times may only be obtained bymaintaining-a constant clearance between the brake `shoe means and thebrake band means, or at least by maintaining an approximate constantclearit; ance between said means. This is usually accomplished byperiodically adjusting the brake mechanism and has proved to be a veryunsatisfactory method, since frequent adjustment is necessary and in agreat many instances the brake mechagg@ mism is not-properly attended toor adjusted as ireuuently as necessary. As a result of this neglect manycars are operated with faulty brakes. lt is the object of my inventionto facilitate the operation of brakes by providing means forautomatically taking up the clearance between the brake drum means andthe brake shoe means.

Another object of my invention is to facilitate the operation oi brakesby providing an automatically operated clearance take up device formaintaining at all times approximately the same amount of clearancebetween the brake drum means and the brake shoe means, while the saidmeans are in an inoperative position;

'Further features of my invention reside in the gg novel means forsupporting the brake shoe means, and in the means for guiding the sameas the clearance between the brake drum and brake shoe means is takenup.

For a more detailed understanding Vof my invention, reference may -behad to the accompanying drawing which illustrates one form which mylinvention may assume, and in which:

Fig. l is a view in elevation ci a brake mechanism incorporating anautomatically operatedA au clearance take up device constructed inaccordance with my invention,A

Fig. 2 is an enlarged view partly in section of' the automaticallyoperated clearance take up device, lili line 3-3 oflig. 2 showing themeans for connecting the take up device with the brake shoe means, and,v

' Fig..4 is a detail sectional view taken o n the llili line l-l of Fig.l showing the means for sup- Fig. 3' is a section taken substantially onthe i (Cl. 18S-79.5)

porting the brake shoes on the fixed back plate. A brake mechanism asillustrated in the 'accompanying drawing is preferablycon'structed andadapted for use with an automobile vehicle and includes a back plate Illwhich is fixed or otherwise secured to a stationary part of the vehicleor chassis and preferably to the axle. A brake drum i i is secured tothe rotating wheel or other movable element with which the brakingmechanism is, associated and a brake shoe means il is preferably mountedinternally ofthe brake drum and arranged to have a predeterminedclearance t with respect to the brake drum. The brake shoe means ispreferably carried by the back plate and for purposes of illustration, Ihave shown a pair of brake shoes although obviously a single shoe may beused, or more than two, it so desired. A pin i3 is carried by the backplate and links it which are pivotally secured to the pin t?, sai-dlinks connecting the brake shoes with the pin, these links each beingpivoted to the web of the brake shoe by means of a pin l5. It will thusbe seen that one, end of each brake shoe m oatably supported by thislink structure and the free ends of the brake shoe are adapted to besecured to a brake shoe actuating mechanism it.

n This actuating mechanism may be operated byV f fluid pressure ifdesired or any other suitable form of mechanical brake shoe actuatingmechanism mayY be employed. Preferably the actuating mechanism hereinillustrated comprises a pair ci pressure actuated elements ita and ithwhich may be secured to the web portion of the iree end of the brakeshoe by means oi suitable pins or other fastening devices il.

in order to maintain the clearance between the brake shoe means and thebrake drum means approximately constant, l have provided anautomatically operated clearance take up device or mechanism which isaadpted to be connected to the brake shoe means and is preferablyconnected thereto adjacent to or close by the irce end or the shoemeans. A pin 2t is carried by the back plate it and projects inwardly ofthe brake drum. The clearance take up device is composed of a pair oitelescoping structures 2l and t2, and the structure 2i including a pin2.3 having an eyelet it for engagement withthe pin iii. This pin 23 isprovided with a tapered portion 25 and the extreme end of the pin remotefrom the eyelet is externally threaded and has adjustably securedthereon a spring retainer 26. A coil spring 21, seating on this springretainer bears against a disc 28 and forces the balls 29 up the taperedportion of the pin 23. The tele- 'gether by the ball clutch.

vWith this structure, very minute clearances secured to the back plate|0, y guide being 'preferablyZ-shaped scoping structure 22 is preferablytubular in cross-section and is telescoped about the inner telescopingstructure 2| the inner surface of the tubular portion of said structure22 engaging the balls 29. Any force which extends to collapse these twotelescoping structures tends to cause the ball to ride up the taperedportion of the pins and to lock the telescoping members together toprevent any further collapsing movement of the same. Any forces tendingto distend these telescoping members tends to cause the balls 29 to ridedown the tapered portion of the pin, thus releasing the two telesco'pingmembers and permitting the same to relatively move axially.

The outer end of the structure 22 is secured to the web of the brakeshoe. A pin 30 is carried by the structure 22 and is engaged in therelatively vshort slot 3| in the web of the brake shoe. The length ofthis slot is determined by the amount of clearance required between.thebrake drum and brake shoe means.

As the braking mechanism is actuated the brake shoes are expanded untilthe brake lining 32 engages the surface of the brake drum. 'If for anyreason the lining is worn and it becomes necessary to move the shoe a`greater distance than is permitted by the slot 3|, the -end of the slotwill engage the pin 30 and exert a force on the structure 22 that willlengthen the clearance take up device, the ball clutch releasing thestructures 2| and 22. shoes are returned to inoperative position theother end of the slot 3| will'engage the `pinf30 and further movement ofthe shoe is prevented because the structures 2| and 22 are locked tomaybe taken up. .In fact as the brake linings wear, the excess clearance isconstantly taken up,` the'automatically operated clearance take updevice being further and further expanded to compensate for the wear inthe brake shoe.

A bracket orguide 35 is riveted or otherwise said bracket or incrosslsection. Theedge 36 of the guide serves as a cam and'is positionedat an angle of approximately 15 to 22 with the horizontal planeginvother words at anangle .to the line of force exerted by actuatingmembers of the brake 4shoe actuating device.,A Thus as the clearance istaken'up the guide engages the clearance take up structure 22Qand urgesthe same downwardly as it is forced outwardly. The shoe which isconnected structure22 is forced downwardly as well as outwardly for thepurpose of maintaining the shoe in proper adjustmentV forv causingthe:shoev tov 'y lengagethe brake drumwith lapproximately the thestructure samepressure throughoutiits entire length. The structure as at.31, the cam portion-36 of the `braclretor guide 35 riding in this'slot.vThe outerl end of 22 `at the bottom of the slot is preferablyrounded'as at 38 to facilitate 'the engagement with the guide or cam 35(see Figs. 2 and 3).

As the brake shoe is adjusted outwardly it will be seen that it is alsomoved downwardly. -The guide thus cooperates with the pivotal linksupport at the lower end of the shoe connected with said link is alsoforced radially outwardly when this adjustment takes place to maintainthe concentric relation between the brake shoe and brake drum.

When the brake shoe or` with the 22 above referred to is slottedaxiallyy Although I have illustrated but one form of my invention andhave described in detail but a single application thereof, it will beapparent to those skilled in the art to which my invention pertains,that various modifications and changes may be made therein withoutdeparting from the spirit of my invention or from the scope of theappended claims.

What I claim as my invention is:

1. In a brake, the combination of a brake drum means, a brake shoe meansarranged to have a predetermined clearance with respect to said brakedrum means, means movably supporting one end of said brake shoe meansand permitting radial movement of same relative to said brake drummeans, brake shoe actuating means engaged with the other end of saidbrake shoe means, an automatically operated clearance take up deviceassociated with said brake shoe means, said device comprising a pair ofpivotally mounted members separated by a plurality of ball members, andmeans cooperating with said brake shoe supporting means for maintainingthe concen- .tric relation between the brake shoe and brake drum meansfor approximately all degrees of adjustment.

2. In a brake, the combination of a brake drum means, a fixed support, abrake shoe means carried by said support and arranged to have apredetermined clearance with respect to said brake drum means, brakeshoe actuating means, and an automatically operated clearance take updevice secured at one end to the support and to the brake shoe means atthe other end,r and cam means carried by the iixed support for engagingsaid clearance take up device to guide the brake shoe means as the sameis adjusted with respect to said brake drum means.

3. In a brake, the combination of a brake drum means a iixed support, abrake shoe means carried by said support and arranged to have apredetersaid brake shoe actuating mechanism, said cam means arranged tobe engaged by saidclearance take up device for guiding the brake shoemeans as the same is adjusted with respect to said brake drum means.

4. In a brake, a drum, a backA plate, brake shoes connected. to theba'ck plate, 'means actuating f said shoes at ladjacent'ends thereof-forengagef'ment with the drum, an automatic take up deviceadapted tomaintain a. predetermined clearance between .the drum andvbrake shoes,said device comprising arpalr vof telescopic members, and meansassociated with said take up device telescopic members thereof formoving one of said brake shoes progressively toward'the drum vtomaintaina concentric relation between said -shoe and drum.

.5. In a brake, a drum, a back plate, brake shoes connected to the backplate, means actuating said shoes ata'djacent ends thereof'forengagementl with the drum, an automatic take up device adapted tomaintain a predetermined clearance between thedrum and brake shoes, saiddevice comprising a plurality ot telescopic members, and meansassociated with said take up device and responsive and responsive to themovement of one of the device comprising .telescopic members separated.lvby a plurality of ball members, and means associated with said take updevice and responsive to the movement of one of the telescopic membersthereof for moving one of said brake shoes progressively toward the drumto maintain a concentric relation between said shoe and drum, said lastnamed means including a cam carried by said plate, said cam operativelyengaging said take up device.

7. In a brake, a drum, a back plate, brake shoes connected to the backplate, means actuating said shoes at adjacent ends thereof forengagement with the drum, a pivot pin carried by the back plate at apoint substantially diametrically opposite said actuated shoe ends, saidshoes having pivoting ends adjacent said pin, links respectively pivotedto the pin and pivoting shoe ends, and a cam member guiding said shoesdownwardly toward said pin and. outwardly with respect to the drumcenter, said cam member being supported on said back plate in a mannerto prevent movement relative to said back plate.

ii. In a brake, a drum, a back plate, brake shoes connected to the backplate, means actuating said shoes at adjacent ends thereof forengagement with the drum, a pivot pin carried by the bach plate at apoint substantially diametricallyv opposite said actuated shoe ends,said shoes having pivoting ends adjacent said pin, links respectivelypivoted to the pin and pivoting shoe ends, and means guiding said shoesdownwardly toward said pin and outwardly with respect to the drumcenter, said last named means including cams flxedly carried by the backplate and respectively acting on said shoes, said last named meansfurther including automatically operated wear take up means formaintaining a constant clearance between said brake shoes and said drum.9. In a brake, the combination of a brake shoe,

a baci: plate, a pin on said brake shoe, a member r pivotally mounted onsaid back plate and said pin, said member being provided with a camportion adjacent said pin, and a bracket member secured to said backplate, said bracket member engaging the camportion of said firstmentioned member. i

10. In a brake, the combination of a brake shoe, a back plate, a memberpivotally mounted on said back plate and said brake shoe, said memberbeing provided with a slot extending longitudinally for a portion of thelength of said member, the slot of said member being provided with a camsurface, and a bracket member secured on said back plate, said bracketmember being provided with a tongue portion extending within the slotand engaging the cam surface of saidfirst mentioned member.

11. In a brake comprising a friction member, an adjustable wear take upmechanism comprising a pair of telescopic members together with a.plurality of ball members therebetween, each of said telescopic membersbeing pivotally mounted, one of said telescopic members being providedwith an external tapered portion, the other of said telescopic membersbeing provided with a straight cylindrical bore.

12. In a brake having a wear adjusting mechanism, the combination of apivotally mounted4 member provided with an external tapered portion, amember telescopically assembled over said pivotally mounted member, anda plurality of rollable members engaging said pivotally mounted l memberand said second mentioned member.

13. In a brake having a. wear adjusting mechanism, the combination of amember having a straight' bore, a member having a conico-cylindricalsurface, a telescopic retainer member slidably mounted on said secondmentioned member, and a plurality of rollable members engaging thestraight Vbore of said iirst mentioned member, said rclla'ble membersfurther engaging the conico-cylindrical surface of said second mentionedmember, said reliable members being retained by said telescopic retainermember, and resilient means suitably mounted to exert a thrust on saidtelescopic retainer member to force said rollable members up theconico-cylindrical surface of said second mentioned member.

14. In a brake, the combination of a drum, a back plate, brake shoes,means actuating said brake shoes at adjacent ends thereof for engagementwith said drum, means pivotally supporting said brake shoes on said backplate, a cam supported by said back plate and acting on one, oi' saidshoes intermediate its actuated end and pivot whereby said brake shoe isprogressively guided downwardly with respect to the axis of said dr'um,and automatically operated wear take up means for maintaining a constantclearance between said brake shoes and said drum, said automaticallyoperated wear take up means being operatively connected with said cam.

JOHN W. TATTER..

